Piquet is the son of three-time Formula One world champion Nelson Piquet, one of Brazil's most successful F1 drivers. Piquet's parents separated soon after he was born, and he lived in Monaco with his Dutch mother, Sylvia Tamsma, until he was eight years old. He then moved to live in Brazil with his father. "They kind of swapped me. My mother wanted me to get to know my father, she wanted me to know Brazil and the language, and she realized life in Brazil would be better for a child."[4] Piquet has two full-sisters, Kelly and Julia, and four half-brothers, Geraldo, Laszlo, Pedro and Marco. He lived in Brasília and attended the American School of Brasília until he was 16 years old, when he decided to pursue his racing career full-time.

Piquet's racing career started in 1993 in Brazilian karting, where he would stay until 2001 when he moved to Formula Three Sudamericana.[5] His father's wealth enabled him to race for his own team, a practice he continued until he left GP2 Series. He raced in part of the 2001 season there, staying for 2002 winning the championship[6] with four races to go. In 2002 he also raced one race of Brazilian Formula Renault.

The 2008 season saw Piquet promoted to the RenaultFormula One race team to drive alongside returning double World Champion Fernando Alonso.[8] It was reported that he gained preference for the seat over Heikki Kovalainen because Kovalainen was seen as a potential rival to Alonso, and such a challenge to Alonso could damage the team.[9]

The first race of the 2008 season in Australia saw Piquet start 21st and damage his car in a collision on the opening lap, before ultimately retiring on lap 31.[10] This was exactly the same result as his father achieved in his first race at the 1978 German Grand Prix. At the Malaysian Grand Prix he started from 13th on the grid and finished 11th.[11] He started the Bahrain Grand Prix from 14th but retired with a gearbox problem after his second pit stop. Piquet qualified in 10th for the Spanish Grand Prix in Barcelona, taking part in the first top 10 qualifying session of his career.[12] However, his race ended on lap seven after colliding with Sébastien Bourdais in an attempt to overtake. The Turkish Grand Prix saw him qualify 17th[13] and finish the race 15th.[14] His problems were further compounded with a pair of non-finishes, when he crashed out at Monaco after failing to get to grips with the damp conditions,[15] and spun off while chasing team-mate Alonso in Canada, before ultimately retiring on lap 42[16] with brake failure.[17]

Piquet was under increasing pressure from his Renault team over the course of the 2008 season, and there was speculation he would lose his race seat if he did not improve.[18][19][20] Renault did nothing to quell the rumours, publicly urging him to improve after the Turkish Grand Prix[21] and suggesting after Monaco that he lacked confidence.[22] Despite the pressure, the young driver responded well. Piquet scored his first points in F1 with a 7th place finish at the 2008 French Grand Prix passing his twice-World Champion team mate Fernando Alonso in the last few laps. In the British Grand Prix at Silverstone, Piquet was at one point lying in fourth place, having passed his team mate who was on old tyres. Piquet aquaplaned and spun out on lap 36 along with several other top runners as the wet conditions reached their worst. A race later, however, at the German Grand Prix, he finished ahead of the Ferrari of Felipe Massa to claim second place to Mclaren's Lewis Hamilton and his first podium finish, after — with a stroke of luck — being the only driver on a one-stop strategy which, with the help of the Safety Car segment, gained him several positions. In Japan however he had his best race of the season, finishing a solid fourth. In the closing laps he was even catching up to Räikkönen and Kubica before making an error.

Despite rumours that he was on his way out, Renault decided to keep Piquet by signing him to a one-year contract.[23] Alonso continued as his teammate hoping to elevate Renault into title contention once again.

Piquet had a disappointing start to the 2009 season, failing to make past the first qualifying session in any of the first three races. His first race, in Australia, ended on lap 24 when he retired with brake failure.[24] He had a better race in Malaysia the following week finishing 13th, two places and only seven seconds behind team-mate Alonso after the race was cut short due to extreme weather. China was another disappointment, however, and after spinning several times and requiring two new nose cones for his car he eventually finished 16th and last, two laps down, in what team manager Flavio Briatore described as a "very, very bad race".[25][26] He had a better race at Bahrain on his way to 10th making up one of the most amount of places behind Webber, whom he held off at the end of the race. In Spain he had a quiet race but was still disappointing after finishing 12th.

At the 2009 Monaco Grand Prix, Piquet was running 10th in a long train of cars being held up by Sebastian Vettel. Piquet's strategy was such that he could have gained many places when those on earlier stops came in, as he was not due to stop until lap 36. He criticised Sébastien Buemi, after the Toro Rosso driver ran into the back of Piquet's Renault, taking them both out of the race. Piquet said, "I'm very angry because Monaco's a long race and that's why these young drivers need to be careful with what they're doing. I don't know what he was thinking there — we planned a long first stint and, if it wasn't for that fool, I could have ended up in seventh."

On 11 September, Renault and Briatore stated they would initiate a criminal case against Piquet Jr. for making false allegations and blackmail. However, on 16 September, Renault announced they would not contest the charges, and that both Briatore and Symonds had left the team.[34][35]

On 21 September, on conclusion of the FIA hearings, Piquet Jr, who was 23 at the time of the 2008 Singapore GP, said "I bitterly regret my actions to follow the orders I was given... My situation at Renault turned into a nightmare. Having dreamed of being a Formula One driver and having worked so hard to get there, I found myself at the mercy of Mr Briatore. His true character, which had previously only been known to those he had treated like this in the past, is now known. Mr Briatore was my manager as well as the team boss, he had my future in his hands but he cared nothing for it. By the time of the Singapore GP he had isolated me and driven me to the lowest point I had ever reached in my life. Now that I am out of that situation I cannot believe that I agreed to the plan, but when it was put to me I felt that I was in no position to refuse."[36] Renault accused Piquet of 'false allegations' and even produced an anonymous "Witness X" who supposedly provided first-hand details of the conspiracy planning, which backed up Pat Symonds' claim that the idea for the crash came from Piquet Jr. himself as a way to atone for poor performance and aid in his negotiations for a contract extension with the team.[37]

However, in December 2010, the Piquets won a libel case in the High Court against Renault. Renault apologised to Piquet for defaming him and paid substantial damages. The Piquets' lawyer said "They were both treated appallingly by Renault F1 when they dared to reveal the scandal to the governing body... F1 has been deprived of the best of Nelsinho and it is to [F1's] detriment that his talent is now being demonstrated elsewhere." Renault issued an apology in response to the High Court decision: "The team accepts that the allegations made by Nelson Piquet Jr. were not false. "It also accepts that Piquet Jr. and his father did not invent these allegations in order to blackmail the team."[38]

On 15 October 2009, Massa was reported as saying he was "certain" Alonso was involved in the scandal, adding, "Without a doubt he knew it."[39] Six weeks later, it was reported that Alonso turned down Massa's charity kart race invitation.[40]

A few hours after Campos confirmed one of its drivers for 2010, website Planet F1 reported that F1 chief executive Bernie Ecclestone hinted at the identity of Bruno Senna's teammate. Ecclestone said in the paddock of the new Yas Marina Circuit that he would like to see the sacked Piquet Jr. get another chance in the wake of the Crashgate affair.[41] "It'd be good wouldn't it, another good name," Ecclestone was quoted by the British Daily Telegraph newspaper as saying, "that's what's being talked about actually."[42]

On December 28, 2009, it was reported by Spanish website Motor21.com that Nelson Piquet Jr. had signed a three-year contract with the new Campos Meta team alongside Senna.[43] However, this was later revealed by Motor21.com to have been a hoax in celebration of the Spanish Día de los Santos Innocentes festival.[44] Piquet himself hinted that he had talks with Force India.[45] However, they opted to retain both Adrian Sutil and Vitantonio Liuzzi, so Piquet decided to move to NASCAR for 2010.[46] Several months later, Piquet admitted he had had talks with more than one F1 team to race again after the crash-gate controversy.[47]

Piquet at his first NASCAR Nationwide Series win at Road America in 2012.

Piquet told Brazilian Rede Globo that he would test a NASCARCamping World Truck Series truck for Red Horse Racing from Rockingham Speedway in North Carolina on October 12, 2009. When asked whether the test could take him down the NASCAR route next season, Piquet said it is not the plan.[48] However, he announced that he will race in NASCAR in 2010—albeit without specifying which series—during the following January.[49] Piquet drives in the Camping World Truck Series with Red Horse Racing,[50] and made his stock car debut in the ARCA RE/MAX Series at Daytona International Speedway driving the #6 Toyota for ARCA powerhouse Eddie Sharp Racing. In his first truck race, Piquet was managed to score a 6th place effort, the first Brazilian driver to finish in the top ten in the series' history. Piquet then announced that he would be competing in three races for Billy Ballew Motorsports driving the #15 truck. The three race deal will start on May 21 at Charlotte Motor Speedway his first race for the team. He will then compete at Texas Motor Speedway and Michigan International Speedway, with the possibility of getting more races.[51] In August, he competed in the NASCAR Nationwide Series race at the Watkins Glen Internationalroad course and finished seventh in his first start in the series.[52] On December 13, 2010, Kevin Harvick, Inc. announced that Piquet would drive a third truck for the team for the full 2011 Truck series season, the #8 Chevrolet with Chris Carrier as crew chief.[53] Piquet ran well during his first season, especially on 1.5 mile tracks, finishing 10th in points as well as being a finalist for Most Popular Driver and runner-up to Joey Coulter for Rookie of the Year.

Piquet signed with Turner Motorsports for 2012 after KHI folded. He drove the full season in Trucks and part-time in the Nationwide Series in 2012. He will drive the No. 30 Chevrolet in the Camping World Truck Series.[54]

On June 23, 2012, Piquet scored his first win in NASCAR competition, winning the Nationwide Series Sargento 200 at Road America; he was the first Brazilian driver to win a NASCAR national touring series event.[56]

On August 18, 2012, Piquet won his first race in the Camping World Truck Series at Michigan. On lap 56 of the race he spun out racing Kurt Busch after a restart. The team pitted under the caution and it allowed them to use fuel strategy later in the race to obtain their first win of the season.[57] On September 29, 2012, Piquet won his second career Camping World Truck Series race at Las Vegas Motor Speedway.[58]